Lubricating system



Dec. 23, 1958 B. J. MITCHELL 2,855,351

LUBRICATING SYSTEM Filed Aug. 23, 1954 2 Sheets-Sheet 1 INVENTCR ATIORNEY V United States Patent LUBRICATIN G SYSTEM Boris J. Mitchell, Birmingham, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application August 23, 1954, Serial No. 451,598 1 Claim. 01. 123-90 The present invention relates to engines and more particularly to the lubrication system therefor.

It is essential that an adequate supply of lubricant be delivered to the working parts of the engine. However, it is just as important that the supply of lubricant is not excessive as otherwise the working parts will be fiooded and this will interfere with the operation thereof. In the past it has been dimcult, if not impossible, to provide a simple and reliable lubrication system which will insure adequate amounts of lubrication flowing to all parts of the valve train during all engine operating conditions without causing an excessive amount of lubricant flooding some of the working parts under some operating conditions. This is particularly true of the moving parts in the valve train.

it is now proposed to provide a lubrication system which is simple and reliable in operation and at the same time will insure the optimum amount of lubricant being provided to all the working parts of the valve train under all engine operating conditions. This is to be accomplished by providing a lubricating gallery inside of the rocker arm shaft and metering means associated with the rocker arms for insuring the desired amount of lubricant. flowing from the rocker arm shaft to the rocker arm and the other elements associated therewith. in order to prevent an excessive amount of lubricant building up in the lubricant gallery in the rocker arm shaft, metering means may be formed by the valve tappets for controlling the flow of lubricantfrom the main lubricant gallery to that in the rocker shaft. Since movement of the tappet is a true index of the amount of movement of the valve train, this will insure the volume of lubricant supplied to the rocker arm shaft being directly proportional to the amount of movement of the parts.

In .the past it has been the practice to provide a removable tappet cover in the side of the engine adjacent the tappets. In order to remove the tappets, etc. it is necessary to remove this cover. To seal this cover to prevent the lubricant escaping therefrom it is necessary to provide a gasket, etc. which adds to the expense of the engine and is a possible source of leaks from gasket failure etc.

It is now proposed to provide a simpleand economical means for removing the tappets etc. from the engine without necessitating the use of a separate removable tappet cover. in order to facilitate the removal of the tappet, the passage that extends through the cylinder block for the push rod may be large enough in diameter to permit the tappet to slide axially therethrough. Thus when the cylinder head has been detached it will be possible for the push rods to be removed and the tappets lifted out through the passage. In order to facilitate the removal of the tappets, a special extracting tool may be provided which is readily insertable through'the passage so that it may grip the tappets and lift them axially out through the passage.

In the drawings:

Fig. l is a cross sectional view of an engine embodying the present invention.

Fig. 2 is a diagrammatic representation of a portion of the lubricating system employed in the engine of Fig. 1.

Fig. 3 is a cross sectional view of the tool for facilitating the removal of the tappets from the engine of Fig. 1.

Referring to the drawings in more detail the present invention may be embodied in an engine 1%) of any suitable type such as a so-called in-line engine. This engine ltl may include a cylinder block 12 having a plurality of parallel cylinders 14 extending therethrough with the upper ends thereof forming circular openings in a planar face 16 on the top of the block 12. The lower ends of the cylinders M may open into a space 17 that extends longitudinally along the bottom of the block 12.

Walls may extend downwardly around the space 17 so that an oil pan 20 may enclose the space 17 and form a crankcase 22. A crankshaft 24 having a plurality of main journals 26 formed thereon may be disposed inside of the crankcase 22 and rotatably supported therein by main bearings in bulkheads 2:8 that extend transversely of the crankcase 22. Thus the crankshaft 24 will be rotatably supported by the bearings with a plurality of hrows 3h projecting radially from the crankshaft 24- in between the bulkheads 23.

A cylinder head 32 may be positioned on the face 16 so as to extend along the top of the cylinder block 12 and close the upper ends of the cylinders 14. A plurality of cavities 34 may be positioned in the cylinder head 32 for communicating with the circular openings created by the upper ends of the cylinders M.

A piston 36 having a cylindrical skirt may be reciprocably disposed in each cylinder 14 with the skirt slidably engaging the walls of the cylinders 14. The upper ends of the pistons 36 may have any desired surface suitable for cooperating with the cavities 34 to form a suitable combustion chamber 33. A connecting rod 40 may be provided for each piston 36 so that the upper end of the rod 4b is attached to a wrist pin 42 in the piston with the lower end connected to one of the radial throws Elli of the crankshaft 24.

An induction and exhaust system 43 and $0, respectively, may be provided for delivering a combustible charge to each of the combustion chambers 33 and for removing the gases therefrom. The induction system 48 may include an intake manifold, a carburetor and intake passages in the cylinder head 32. The intake passages 52 may extend through the head. 32 with the outer ends comprising intake ports spaced along one side of the head 32. The inner ends of the passages 52 may extend into the combustion chambers 38 and form a valve seat 54 in the walls thereof. The. intake manifold which has a carburetor mounted thereon may be secured to the engine ill to register with the intake ports so the combustible charge developed by the carburetor may be delivered to the combustion chambers 38 via the intake passages A valve 56 may be disposed in each of the intake valve seats 54 for controlling the flow of the charge through the intake passage 52 into the combustion chambers. 38.

The exhaust system may include an exhaust manifold and a plurality of exhaust passages that extend through the head with the outer end thereof discharging into the exhaust manifold and the inner ends extending into the combustion chamber 38 to form an exhaust valve seat similar to the intake valve seat. An exhaust valve similar to the intake valves may be provided in each of the exhaust valve seats forcontrolling-the how of exhaust gases out of the combustion .chambenfgtl and into the exhaust manifold via the exhaust passages.

A valve train 60 may be provided for opening and closing the intake and exhaust valves 56 at the proper moment to insure the induction and eduction of the gases for the combustion chamber 38. In the present instance this valve train 60 starts with a camshaft 62 that extends longitudinally of the engine to be rotated by the crankshaft 24 at one-half engine speed. A tappet 64 may be provided for each of the valves. In the present instance these tappets 64 are hydraulic slack adjusters having an annular recess 66 extending around the middle thereof so that the lubricant can enter into the interior of the adjuster and the working parts thereof. These tappets 64 may be slidably disposed in guides 68 so that the lower ends thereof will engage the earns 70 on the camshaft 62. A push rod 72 may be slidably disposed in each of the substantially vertical passages 74 that extend upwardly from the tappets 64 through the head 32 and cylinder block 12. The lower end of each push rod 72 may seat inside of one of the tappets 64-, while the upper ends of the push rods 72 may engage one end of a rocker arm 76 that is pivotally mounted on a rocker arm shaft 78. The rocker arm shaft 78 may be a hollow tube having a passage 80 extending therethrough and it may be mounted on brackets 82 projecting from the top of the cylinder head 32. Rocker bracket bolts 81 may be threaded into holes 83 for securing the brackets 82 to the head 32. The other ends of the rocker arms 76 may be free to engage the stem 84 of one of the intake or exhaust valves 56. Thus it may be seen that as the camshaft 62 rotates the various cams 7t} thereon will engage the tappets 64 and cause the push rod 72 to rise and force the rocker arms 76 to rotate about the rocker arm shaft 78. This in turn will cause the valve stem 84 to be depressed and the valve 56 opened. When the cam 70 has rotated sufficiently to allow the tappet 64 to return to its original position, a spring 86 biasing the valve 56 towards the closed position will cause the valve 56 to close and force the rocker arm 76 and push rod 72 back to their original positions.

In order to insure proper lubrication of this valve train, a duct 88 may extend longitudinally through the cylinder block 12 to intersect the tappet guides 68 and form openings 91) in the sides thereof which are positioned to communicate 'with the recess 66 in the tappet 64. This duct 88 may be connected to any suitable source of lubricant such as an oil pump (not shown) whichwill force lubricants to how into the duct 88. In order to allow the lubricant to flow from this duct 88 to the passage 8%) inside of the rocker arm shaft 78, one or more conduits 92 may be provided. In the present instance the conduit 92 is drilled into the block 12 so that the lower end thereof forms a port 94 in the wall of one of the valve guides 68 adjacent an opening 90 formed by the duct 88. The upper end of the conduit 92 may intersect the rocker bracket bolt hole 83. At least a portion of this hole 83 i is preferably slightly over size so that there will be sufficient clearance space 85 around the bolt 82 for the lubricant to fiow upwardly therethrough into the center of the rocker arm shaft 78. The port 94 formed in the wall of the guide 68 by the lower end of the conduit 92 is preferably disposed slightly above the openings 90 formed by the ducts 88. Thus when the tappet 64 is in its normal or valve closed position, the annular recess 66 will register with the openings 90 formed by the duct 88 but it will not register with the port 94. This will allow the lubricant to flow in and around the tappet 64 but not into the conduit 92. However, when the cam 70 raises the tappet 64 for opening the valve 56, at least a portion of the recess 66 will simultaneously register with both the port 94 and the opening 90. Thus the lubricant may flow from the duct 88 into the conduit 92 and rocker arm shaft 78 when the valve is open and only then. It should be noted that this operation (the opening of the valve 56 and the uncovering of the port 94) will occur during every other revolution of the engine regardless of the engine operating conditions. Accordingly, the size of the port may be proportioned to pass the optimum amount of lubricant for lubricating the valve train during two revolutions of the engine.

After the movement of the tappet 64 has allowed the desired amount of lubricant to pass into the conduit 92, it will flow up through the rocker bracket bolt hole 83 into the lubricant gallery inside of the rocker arm shaft 78. This lubricant may then flow from the gallery 80 to the moving parts of the valve train by any suitable means. In the present instance the lubricant is distributed by means of drilled passages 96 in the rocker arms 76 and openings 98 in the rocker arm shaft 78. The lubricant may flow from the openings 98 to the passages 96 by means of the working clearance between the shaft 78 and the arm 76, or the passage 96 in the arm 76 and the opening 98 in the shaft 78 may be positioned so that they will register when-the arm 76 is in one of its extreme positions. In any event the proportions of the passages, openings, etc. may be such as to allow the optimum amount of lubricant to flow through the passage 96 and be discharged over the exterior of the rocker arm 76 from whence it will drain down over all the parts of the train 60 and return to the sump in the oil pan 20.

In order to facilitate removal of the tappets 64 from the engine 10 the portion of the passage 74 for the push rod 72 in the block 12 may be large enough to permit the tappet 64 to be moved axially therethrough. Thus when the cylinder head 32 is removed, the tappet 64 maybe lifted from the engine 10 through the passage 74. It can thus be seen that there is no necessity for providing a removable tappet cover for allowing access, to the tappets 64. Since the space in and around the passage 74 is very limited, an extractor tool 100 may be provided. In the present instance this tool 100 includes a handle 102 and a tubular barrel portion 104. The barrel portion 104 may have a passage 106 extending axially therethrough with the lower end thereof having a plurality of radially expansible fingers 108. These fingers 108 are adapted to be inserted into the open end of the tappet 64 and engage an annular groove 110 formed inside of the tappet 64. A rod 112 may extend through the passage 74 in the barrel 104 with a tapered end 114 being disposed adjacent the interior of the fingers 108. Thus when the outer end of the rod 112 is pushed, the rod 112 moves axially through the barrel 104 and the tapered end 114 will spread the fingers 108 in a radial direction.

It is thus apparent that when the cylinder head 32 and push rod 72 are removed the tool 100 may be inserted through the passage 74 to place the fingers 108 adjacent the grooves 110 in the tappets 64. If the upper end of the rod 112 is depressed the fingers 108 will spread and lock in the groove 110. The operator may then lift the tappet 64 axially out through the passage 74.

It is to be understood that, although the invention has been described with specific reference to a particular embodiment thereof, it is not to be so limited since changes and alterations therein may be made which are within the full intended scope of this invention as defined by the appended claim.

What is claimed is:

An engine having a valve train including a rocker arm having a support and a tappet having a guide and a camshaft having a bearing and reciprocating said tappet and a push rod between said tappet and said rocker arm, and comprising a lubricating system including a source of lubricant under pressure, a supply passage connected to said source and having an end forming a port on the inner surface of said guide member, a recess on the outer surface of said tappet and positioned to communicate with said supply port throughout the reciprocating movement of said tappet, a distribution passage connected to said rocker arm and having an end forming another port on the inner surface of said guide member, said another port being disposed opposite said recess and in communication therewith when said tappet is at one end of the reciprocating movement thereof and being disposed remotely from said recess and out of communication therewith when said tappet is at the opposite end of the reciprocating movement thereof, said tappet being in continuous communication With said supply port through said recess and throughout the reciprocating movement of said tappet.

1,496,134 Rumgay June 3, 1924 6 Merdian Sept. 6, Coleman June 7, Biewend et al Mar. 3, Heiss Aug. 10, Willgoos July 12, Spencer May 16, Witzky et al Nov. 25, 

